The lawsuit, filed in U.S. District Court in Phoenix on behalf of activist groups Puente Arizona and Poder in Action, and four named residents, claims police used excessive force while dispersing crowds outside of the Phoenix Convention Center on Aug. 22, 2017.

Officers fired more than 590 projectiles "indiscriminately" into a crowd that "included children, elderly people, disabled people, and pregnant women," the lawsuit said.

"Under the direction of Chief Williams, Phoenix police disregarded the constitutional rights of protesters that night," said ACLU of Arizona Legal Director Kathy Brody in a statement.

"At the precise moment when anti-Trump protesters intended to deliver to the president and his supporters their messages renouncing his policies, Phoenix police — without warning — used incapacitating weaponry to silence and disperse hundreds of peaceful anti-Trump protesters."

The lawsuit was filed by the Arizona chapter of the ACLU, Los Angeles-based law firm Hadsell Stormer & Renick LLP and civil rights attorney Dan Pochoda. Plaintiffs are requesting a court bar Phoenix police from using excessive force against protesters in the future and are also seeking financial rewards.

Ira Yedlin, 70, protested at President Trump's rally in Phoenix, Aug. 22, 2017. While many left with irritated eyes after police used pepper balls, Yedlin says he was more seriously injured after being hit with a projectile. Jason Pohl/azcentral.com

Among those listed as plaintiffs in the lawsuit is Ira Yedlin, a 70-year-old man from Bisbee who traveled to protest Trump. Speaking to The Arizona Republic in the days after the protest, Yedlin said he was a lifelong protester, but what happened as crowds dispersed from the Phoenix rally was unlike anything he had witnessed before.

"I've been at, over the last 50 years, dozens of protests," he said previously. "Never have I seen a police reaction like that without any apparent provocation."

"The tragedies that happened in other cities did not happen in Phoenix," she said, referring to the deadly demonstrations in Charlottesville, Virginia, that occurred just days before Trump's appearance in Phoenix.

A 31-page report issued earlier this year provided a harsher self-assessment than the police department had offered in the past. It detailed the ammunition used against the crowd, as well as a timeline of events.

In a section titled "Opportunities for Improvement," the report's suggestions include a "proactive notification process" to communicate with groups causing disorder, greater use of social media and tools — like megaphones — to keep the public informed in real time, and to provide warnings in both English and Spanish.

At 8:34 p.m., police donned gas masks and requested an air unit to illuminate the area and make announcements to disperse. Police officials initially said the gas masks alone should have been a warning to protesters, a point protesters later would criticize.

The report also shows there was a lag in the time the Air Unit was given instructions to warn protesters and when the announcement was actually made. The report's authors attribute the delay to waiting for clearance from the Federal Aviation Administration. Officers began using their weapons at 8:35 p.m., and the Air Unit announcements kicked out at 8:52 p.m.

CLOSE

Phoenix police have edited and provided this compilation of footage from the entire day of President Donald Trump's Aug. 22, 2017, rally.

None of the officers involved were disciplined.

According to the report, one officer deployed a smoke grenade and two tear gas grenades without receiving direction from the field commander. When asked why he was not disciplined, a Phoenix police spokesman said the officer was certified to use the equipment and was responding to a dynamic situation.

Activist groups have continued to reel from the use-of-force incident, something that has had a chilling effect on subsequent demonstrations in the past 13 months, attorneys said.

"Absent the court’s intervention, those who wish to gather and speak will continue to experience understandable fear of police retaliation when participating in protests, demonstrations, and marches, particularly when expressing anti-Trump views," attorneys wrote.

The 47-page lawsuit also called attention to the surge in police shootings across Phoenix this year. There have been 37 police shootings this year, an unprecedented record that translates, on average, to one incident each week. There were 21 shootings in all of 2017, 25 in 2016 and 17 in 2015.

“The Phoenix Police Department’s epidemic of violence is a crisis in our community,” Viri Hernandez, executive director of Phoenix-based Poder in Action, wrote in a statement. “The police violence we saw at the anti-Trump protest is the same police violence that has caused Phoenix to lead the nation in officer-involved shootings. The lack of accountability for police violence by the mayor, city council, and Chief Williams is inexcusable.”

Reach the reporter at 602-444-8515, jpohl@azcentral.com or on Twitter: @pohl_jason

Protesters leave the scene after Phoenix police used gas outside the Phoenix Convention Center on Aug. 22, 2017, in Phoenix. Protests were held against President Donald Trump as he hosted a rally inside the convention center. Associated Press

Protesters raise their hands after Phoenix police used gas outside the Phoenix Convention Center on Aug. 22, 2017, in Phoenix. Protests were held against President Donald Trump as he hosted a rally inside the convention center. Associated Press

Smoke billows after Phoenix police used gas outside the Phoenix Convention Center on Aug. 22, 2017, in Phoenix. Protests were held against President Donald Trump as he hosted a rally inside the convention center. Associated Press

Protesters yell after Phoenix police used gas outside the Phoenix Convention Center on Aug. 22, 2017, in Phoenix. Protests were held against President Donald Trump as he hosted a rally inside the convention center. Associated Press

Phoenix police move protesters away after using tear gas outside the Phoenix Convention Center on Aug. 22, 2017, in Phoenix. Protests were held against President Donald Trump as he hosted a rally inside the convention center. Associated Press

Phoenix police move protesters away after using gas outside the Phoenix Convention Center on Aug. 22, 2017, in Phoenix. Protests were held against President Donald Trump as he hosted a rally inside the convention center. Associated Press